Hi Madusa
The Tapco 20 round Mags are very dependable. I did the bolt modification that you are talking about. I had a SKS m at the time so it was easy to copy that bolt to make my other SKS able to accept the mag without holding the bolt back. Here is a article about the bolt mod and Kivaari is the trigger guru. http://www.sksboards.com/smf/index.php?topic=23876.0